Rando-Web Process

From bale to nonwoven web in one continuous operation...

Refer to the diagram of the Rando-Web® Process above to trace the stock/fiber flow through the equipment. Code numbers are provided underneath the diagram and in the descriptive copy below to help you follow the flow of the fiber through the Rando-Web® manufacturing process.
 

Rando Bale Opener

Bales, normally two, are placed side by side with the layers running horizontally onto the floor apron (1) of the Rando Bale Opener. The bales are fed forward into spiked beater rolls (2) which pluck small tuffs of fiber from the bales and transfer them onto the floor apron (5) in the hopper area. The floor apron (5) of the Rando Bale Opener introduces the stock to the elevating apron (3). The stock on the pins of the elevating apron passes over the top and is discharged by the doffer roll (6) at a uniform rate through a chute or optional weigh pan. Excess stock on the elevating apron is removed by the stripper apron (4) and returns to the hopper area. The on/off fiber feeding function of the Rando Bale Opener is controlled by a photo-eye mounted to the machine. The fiber is received, usually by either the Rando Prefeeder or the Rando Feeder, depending upon the specific application.
 

Rando Prefeeder

Fiber from the Rando Bale Opener, or if a Rando Bale Opener is not required, stock in dry fiber form as slabs from the bale is manually deposited into the loading area of the Rando Prefeeder and onto the extended floor apron (7). On demand from a signal transmitted by a photo-eye located in the hopper area, the fiber is feed into the floor apron (8) in the hopper area. The floor apron in the hopper area of the Rando Prefeeder introduces the stock to the elevating apron (9). The stock on the pins of the elevating apron passes over the top and is discharged by the doffer roll (11) at a uniform rate through a chute or optional weigh pan into the Rando-Opener Blender. The excess stock on the elevating apron is removed by the stripper apron (10) and returns to the hopper of the Rando Prefeeder. The action of the elevating and stripper aprons reduces the slabs of fiber to high density tufts. The fibers from the Rando Prefeeder are normally deposited into the Rando Opener/Blender. The on/off fiber feeding function of the Rando Prefeeder is controlled by a photo-eye mounted in the hopper area of the Rando Feeder.
 

Rando Open/Blender

The floor apron (12) of the Rando Opener/Blender carries the high density tufts of fiber to the two worker rolls (14 & 15). These wire clothed rolls take a small amount of fiber for opening. The kicker roll (13) takes the excess fiber, and because of its rotation, the fiber circulates in the hopper area. An adequate supply of circling fiber is important at all times to achieve desired production rates. The partially opened fiber passes from the two worker rolls to the main cylinder (16) where additional opening and blending takes place. It also conveys the fiber to three pairs of small metallic wire clothed transfer rolls (17) for additional working. From the main cylinder, the opened fiber is doffed mechanically by the doffer roll (18). The doffer roll generates a high velocity air stream, which carries the fiber from the Rando Opener/Blender through the discharge chute (19), into the fiber separator (20) area of the Rando Feeder. In the Fiber Separator, the opened fiber and high velocity air are separated. The Rando Opener/Blender is turned on at all times while the Rando-Web® Process system is running.
 

Rando Feeder

The opened fiber drops from the Fiber Separator (20) onto the floor apron (21) of the Rando Feeder. The floor apron carries the stock to the pinned elevator apron (22), which raises the fiber to the pinned stripper apron (23). At this point, the excess stock is removed by the stripper apron and returns to the hopper of the Rando Feeder. The small opened tufts of fiber remaining on the pins of the elevating apron pass over the top and into an area known as the Air Bridge – the area between the front of the elevator apron and the feed mat condenser. Doffing of the fiber is accomplished by the flow of air over the pins of the elevating apron into the Air Bridge. The flow rate of this air determines the quantity of stock conveyed to form a continuous feed mat on the feed mat condenser (24). Since the air pressure above the feed mat condenser screen is below atmospheric pressure, air must flow through the condenser screen into the suction duct. As the feed mat takes shape, the air flow is cut down by the resistance of the feed mat on the condenser screen and in the throat of the Air Bridge. Proportionally less doffing occurs until a condition of equilibrium is reached. At this point, just enough tufts are doffed to form a continuous, uniform feed mat.
 

Rando Webber

The feed mat is doffed from the Rando Feeder, which is synchronized with the feed roll drive in the Rando Webber®, onto the feed plate and under the feed roll (28) of the Rando Webber®. The feed roll feeds the mat into the concaved surface of the nose bar (29) and exerts holding-action as the feed mat is fed over the top of the nose bar and into the path of the lickerin (27). Individual fibers are combed from the feed mat by the lickerin and introduced into the air stream generated by the Rando Webber pressure fans (31). The velocity of the air is controlled by the saber (33), which is set in eccentric bushings. When rotated, the opening between the saber and the lickerin narrows and widens, increasing or decreasing the air velocity much in the manner of a venturi. The airborne fiber is carried in the duct area to the condenser for forming the Rando-Web® (30). Here the fiber is uniformly deposited with the assistance of vacuum air from the vacuum fans (32). It’s pulled through the condenser onto either the revolving condenser screen of the “SB” style forming conveyor or the linear running “SD” style forming conveyor. At this point, it is aerodynamically formed into a continuous random fiber web structure. The result is a continuous Rando-Web® Process, with the web flowing from the condenser screen out of the Rando Webber®.

Rando Web Process

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